Liquid motion lamps, a type of novelty display, may include a sealed transparent container that holds a colorful fluid. The fluid may include a number of immiscible components such as dyed liquids, solids and gases. The fluid may be circulated or agitated within the container to produce random flow patterns and interesting visual effects. Various techniques have been used for creating desired motion in the fluid. One common method utilizes natural convection wherein a light bulb or electric heater is used to warm the fluid. Other methods incorporate motors or pumps to force motion in the fluid.
A popular design for a liquid motion lamp, such as the Lava® brand motion lamp manufactured by Haggerty Enterprises, Inc., Chicago, Ill., is based on natural convection and uses a fluid that may include water and paraffin wax. The fluid is sealed within a glass bottle that rests on a solid base. An incandescent light bulb is concealed within the base and heats and illuminates the fluid through the glass bottle and an opening in the base. The wax undergoes a continuous solid-to-liquid-to-solid phase transition as it is heated and cooled thus causing it to rise and fall within the water. Interesting visual effects result from the motion of the wax.
However, due to the large thermal mass of the device, the start-up time is approximately two hours resulting in a long period of inactivity and poor electrical efficiency. Efforts have been made to reduce the size of the lamp, however its miniaturization is limited by practicality—it should be large enough to be viewable from anywhere in an average sized room. Further, the device weighs approximately two kilograms thus increasing its cost and limiting its utility. Still further, the choice of a glass bottle for a container limits the ruggedness of the device. Additionally, the device sustains a luminous flux sufficient to illuminate the fluid but substantially less than that of a typical household light fixture—rendering it unsuitable for general use in room lighting.
There is therefore a need for a liquid motion display that has a short warm-up time and is efficient, lightweight, inexpensive, rugged, and bright.